Sorry I missed your system info before. Thanks for that.
Could you please make sure all your Modern Tribe plugins (and WordPress core) are at their latest versions?
Once you verify you’re on the latest versions, please test to see if the issue is still happening for you.
If it is, please follow our Testing for Conflicts Guide and see if that helps narrow down the cause of this (you may need to create a new event to test if it’s working).
Let us know what you find out.
Thanks.